The Effect of Police on Crime: New Evidence from U.S. Cities, 1960-2010

We argue that the key impediment to accurate measurement of the effect of police on crime is not necessarily simultaneity bias, but bias due to mismeasurement of police. Using a new panel data set on crime in medium to large U.S. cities over 1960- 2010, we obtain measurement error corrected estimates of the police elasticity of the cost-weighted sum of crimes of roughly -0.5. The estimates confirm a controversial finding from the previous literature that police reduce violent crime more so than property crime.